Objectives: 1. To explore by a case-control study detailed factors of possible etiologic significance in the occurrence of prostatic cancer. Though focusing primarily on variables relevant to both sexual and venereal hypotheses, occupational history, smoking and alcohol consumption and dietary factors will also be explored. 2. To determine whether differences in endocrine patterns exist between prostatic cancer cases and normal controls as an initial step to their establishment as risk factors and possible screening tools for prevention. (Though blood will be available for hormonal studies in addition to herpesvirus 2 antibody determination, aliquots for the former will be stored frozen for such studies in the future as will be urine specimens). Methods: It is proposed to identify 200 prostatic cancer cases among white males under 75 years of age in those hospitals in the Twin City area with the largest average annual case load of such newly diagnosed cancers. For each of these, a hospital control without genito-urinary disease or cancer will be matched by age, race and admission date, and a neighborhood control matched by age and race will be selected. Samples of blood will be drawn for herpesvirus type 2 antibody study prior to surgery or hormone therapy among the cases and similar bloods from the controls. Aliquots of blood and specimens of urine will be frozen for later hormonal studies, e.g., estriol, estridiol, estrone, N-androstenedione and dehydro and rosterone. Each subject will be interviewed via a structured questionnaire for the relevant variables included in the categories mentioned under "objectives" above.